Washing machine

ABSTRACT

A WASHING MACHINE WHICH COMPRISES A TIME SWITCH PROVIDING A SERIES OF AUTOMATIC TIME CYCLES RANGING FROM WASHING CYCLE THROUGH RINSING CYCLE TO DRAINING CYCLE, AND IN WHICH PARTICULARLY DURING THE RINSING CYCLE A PHOTOSENSITIVE ELEMENT DETECTS THE TRANSPARENCY OF THE RINSING WATER, THEREBY AUTOMATICALLY DETECTING THE COMPLETION OF THE RINSING OPERATION OR A POINT OF TIME AT WHICH THE CONCENTRATION OF THE DETERGENT IN THE RINSING WATER IS LOWER THAN A PREDETERMINED LEVEL, SO THAT A SERIES OF SUBSEQUENT TIME CYCLES TAKES PLACE.

Filed Nov. 13, 1969 KAZUO SHIMOKUSU ETAL WASHING MACHINE 6 Sheets-Sheet 1 KAzuo sHxMoKusu TAKASH: KoREKAwA ToMoYuKl HosoKAwA 'TARo lYAMAMOTO TAKAo KOBAYASI l lNVENToRs ATTORNEYS Oct. 19, 19.71 KAZUC)- sHlMOKUSU ETAL 3,613,405

WASHING MACHINE e sheets-sheet z Filed Nov.-. v13. 1969 2 4 HNS/N6 r/ME WASHING MACHINE 6 Sheets-Sheet 5 Filed Nov. 15, 1969 RATE 0F WATER SUPPLY (/M//vl Oct- 19, '1?71 KAzUo sHlMoKUsu ET AL WASHING MACHINE 6 Sheets-Sheet l.

Filed Nqv 13, 1969 Oct. 19,1971 KAzuo sHlMoKusU ET AL 3,613,405

. WASHING MACHINE Filed NOV. l5, 1969 6 Sheets-Sheet 5 Oct. 19,1971 KAZUO 5|||MOKUSU ET AL 3,613,405

WASHING MACHINE Filed Nov. 13, 1969 6 Sheets-Sheet 6 ll W Il fyi-+2721? lF27? Ir- Y l 1 1 l l l l 6;@2 *H l T l 59 i V11 VH'. -L l 5 l 5 United States Patent C) 3,613,405 WASHING MACHINE Kazuo Shimokusu and Takashi Korekawa, Osaka,

Tomoyuki Hosokawa, Takarazuka-shi, Taro Yamamoto, Kyoto, and Takao Kobayasi, Toyouaka-shi, Japan, assignors to Matsushita Electric Industrial Co., Ltd., Osaka, Japan Filed Nov. 13, 1969, Ser. No. 876,283 Claims priority, application Japan, Nov. 1S, 1968, 43/84,350 Int. Cl. D06f 33/02 U.S. Cl. 68-12 R 5 Claims ABSTRACT OF THE DISCLOSURE A washing machine which comprises a time switch providing a series of automatic time cycles ranging from washing cycle through rinsing cycle to draining cycle, and in which particularly during the rinsing cycle a photosensitive element detects the transparency of the rinsing Water, thereby automatically detecting the completion of the rinsing operation or a point of time at which the concentration of the detergent in the rinsing water is lower than a predetermined level, so that a series of subsequent time cycles takes place.

This invention relates to a washing machine. The rinsing operation effected by a washing machine is intended to remove dirt and detergent sticking to fiber products and thereby make the fiber products clean. The length of time required for rinsing greatly varies with the quantity of the detergent and water used for the washing purpose.

According to the prior art washing machines having a time switch, it has usually been the practice for the user to set the rinsing time judging from his past experience, taking into account such factors as the quantity of the clothes to be washed, the degree of dirt, the quantity of the detergent and water to be used. Alternatively, in the entirely automatic washing machine, the rinsing is effected for a fixed length of time in accordance with a program determined by the manufacturer of the washing machine.

In any of these cases, the amount of rinsing operation to be effected by the washing machine has been determined in terms of time, and this has often caused the rinsing operation to continue for a longer time than necessary to thereby injure the quality of the fiber material as Well as to Waste water and power, or in some instances it has resulted in such an incomplete or insufficient rinsing effect that another rinsing operation is required.

It is an object of the present invention to always detect a proper point of time for the completion of the rinsing irrespective of various washing conditions.

It is another object of the present invention to provide an improved electrical circuit for effectively and properly accomplishing the detection of the completion of rinsing.

It is still another object of the present invention to provide a simple time switch arrangement for stopping the main cam group of the time switch until the rinsing is completed, in cooperation with the operation of the electrical circuit detecting the completion of rinsing.

It is yet another object of the present invention to provide an arrangement for making the function of the rinsing detection relates to the operation of a pulsator and thereby eliminate any erroneous detection.

It is yet still another object of the present invention to provide various improved means associated with a sampling box provided with a luminous element and a photosensitive element so as to accomplish reliable rinsing detection.

These and other objects and features of the present invention will become fully apparent from the following description given with reference to the accompanying drawings, in which:

FIG. 1 is a vertical sectional View of the washing machine according to a preferred embodiment of the present invention, particularly showing the piping arrangement associated with the rinsing detection means;

FIG. 2 is an enlarged sectional view showing the rinsing detection means;

FIG. 3 is a graph for illustrating the relationship between the rinsing time and the transparency of the water;

FIG. 4 is a graph for illustrating the relationship between the rinsing time and the resistance of the CdS;

FIG. 5 is a graph for illustrating the relationship between the quantity of water supplied and the dilution ratio;

FIG. 6 is a block diagram of the electrical circuit in the present invention;

FIG. 7 is an elevational view showing the gear train used inthe time switch;

FIG. 8 is a chart showing the time cycles provided by the time switch;

FIG. 9 shows a part of the chart of FIG. 8 in greater detail; and

FIG. 10 is an enlarged sectional view showing another example of the rinsing detection means according to the present invention.

Referring to FIG. 1, there is shown the water circuit in the washing machine according to an embodiment of the present invention. The washing machine includes a washing drum 1, a pulsator 2, an overflow port 3, a drain hose 4, a drain valve S, a water supply port 6, a sampling box 7 for detecting the concentration of a detergent, a luminous element 8 such as an incandescent lamp, and a photosensitive element 9 such as a CdS cell. During the rinsing operation water is continuously supplied through the Water supply port 6 to cause the water in the washing drum to overflow through the overflow port 3. The overflow passes through the sampling box 7 to be discharged through the drain hose 4.

Turning to FIG. 2, there is shown an enlarged View of the sampling box 7, which includes an inlet pipe 10 communicating with the overflow port 3, an outlet port 11, an air hole 12, a projector window 14 formed of a material such as transparent glass or resin transmitting therethrough a sufficient quantity of light from the luminous element 8, and a light receiving window 15 formed of a material having the same properties as the projector window 14.

As shown, the luminous element 8 and photosensitive element 9 are disposed in a vertically opposed relationship with the sampling box 7 interposed therebetween. The photosensitive element 9 is so arranged that it depends solely on the luminous element 8 for its light source and receives no other extraneous light such as the sunlight, etc.

Assume that the rinsing operation is going on with the overflow from the washing drum 1 passing through the inlet pipe 10 down into the sampling box 7. When the overflow falls into the sampling box 7, it imparts shocks to the water in the sampling box to thereby create bubbles 13 which will rise toward the air hole 12 because of their buoyancy, while the water flows across the sampling box 7 toward the outlet 11. In this way, the sampling box 7 will be lled with bubbles except at that portion which receives the falling overflow. In this state, the beams of light from the luminous element 8 are substantially prevented from reaching the photosensitive element 9 by the bubbles 13 filling the sampling box 7. However, when the concentration of the detergent solved in the overflow reaches a level below a certain value, the

surface tension of the water in the sampling box will no longer allow the shocks imparted by the falling overflow to create such bubbles, whereupon the quantity of light reaching the photosensitive element 9 will sharply increase. Thus, if this point of time is determined as the point of time for the completion of rinsing operation, it will be possible to automatically detect the completion of the rinsing.

This relationship is shown in FIG. 3 which represents the experimental data indicating the variation of the illumination on the surface of the photosensitive element 9.

In operation, the luminous element is activated under a predetermined condition and the water supply is started at a predetermined ow rate (eg. litres per minute) to llow into the washing water containing a predetermined quantity of synthetic detergent solvent therein. As seen in the graph of FIG. 3, during the initial stage of the rinsing operation, or when the detergent is still contained in the water, the illutnination on the surface of the photosensitive element 9 is about l lux. At the point of time when the rinsing has been completed, the illumination becomes 23 luxes, which means an increase of illumination exceeding twenty times the initial level. The illustrated embodiment employs CdS which is a typical material for the photosensitive element, and the variation in the resistance thereof is shown in the graph of FIG. 4.

The resistance of CdS is 9 kQ at the initial stage of the rinsing operation, but it begins to decline sharply 4 minutes later, and becomes 0.8 kt) 8 minutes later. This value is in accord with the level A for pure water, i.e. Water which is completely free of any detergent, The values shown below the rinsing time in FIG. 4 indicate the dilution ratio of the detergent which changes from time to time, and these values can be theoretically determined from the quantity of the water supplied with respect to time.

Sucient rinsing effect may be provided if the dilution ratio is 100 or higher. However, assuming that the dilution ratio is set to 160, the level B represents the required operating level of the detector. Thus, when the resistance value of CdS becomes l kt?, the control circuit which will be described hereinafter operates detecting the completion of rinsing. It is possible, however, to set the dilution ratio to any desired value by adjusting the control circuit.

FIG. 5 is a graph for comparing the degree of rinsing effect accomplished by the prior art washing machine using the time control with that accomplished by the washing machine according to the present invention. It is seen from this graph that according to the prior art rinsing remains insucient if the rate of water supply is low, while it is excessively effected if the rate of water supply is high. In contrast, according to the present invention, the rinsing operation can be automatically carried out at a predetermined dilution ratio or at a predetermined rate of rinsing, irrespective of the rate of water supply. Thus, the rinsing operation is completed within a shorter time if the water supply is greater, and it is continued until a predetermined dilution ratio is reached, if the water supply is smaller. This means that the rinsing operation never stops before the satisfactory result is achieved.

FIG. 6 shows an example of the entire electrical circuit incorporated in the washing machine according to the present invention. The portion of the shown circuit which is encircled by the dotted line S relates to the control of a series of operative cycles, i.e. water supply, Washing, drainage, water supply, rinsing, drainage, as in the conventional washing machine. The other portion of the circuit encircled by the dash-and-dot line K is a control circuit for detecting the completion of the rinsing operation.

`Description will now be made of the illustrated electrical circuit. The electrical circuit includes an A.C. power source having one end thereof connected with one end of a switch S4 or 2l contained in the time switch.

The switch S1 or 21 is a main switch through which the user of the washing machine can turn on or olf the power to the entire circuit. The other end of the switch S1 or 21 is connected with the common contact of a switch S2 or 22. The contact a of the switch S2 or 22 is connected with the common contact to a water level switch S4 or 24, whose contact a is connected with one end of the solenoid of a water supply valve 30. The other end of the solenoid of the water supply valve 30 is connected with the other end of the A.C. power source 20. The contact b of the switch S4 or 24 is connected with the common contact of a switch S6 or 26 contained in the time switch, and the contacts a and b of the switch S6 or 26 are connected with the windings of a pulsator drive motor 29, respectively. The switch S6 or 26 is changed over from the contact u to b or conversely every 30 seconds so as to automatically reverse the pulsator drive motor 29 from its clockwise rotation to its counter-clockwise rotation. The switch S3 or 23 connects the common contact of the switch S4 or 24 with the contact fz of the same switch, so that when the rinsing cycle begins the switch S3 or 23 is closed to actuate the water supply valve 30 so as to allow water to be supplied therethrough, irrespective of the position of the switch S4 or 24.

The contact b of the switch S2 or 22 is connected with one end of the solenoid of the drain valve 27, the other end of which is connected with the other side of the A.C. power source 20. The common contact of the switch S or 25 is connected with the other end of the power source via the time switch drive motor 28, and the Contact a of the switch S5 or 25 is connected with the contact b of the switch S4 or 24. The contact b of the switch S5 or 25 is connected with the contact b of the switch S2 or 22. When the common contact of the switch S2 otr 22 is engaged with the contact a, the common contact of the switch S5 or 25 is also engaged with the contact a thereof. That is, these two switches are operatively interlinked. Further, in parallel with the water supply valve is connected the primary winding of a transformer 31 for supplying a necessary power to the control circuit, and the secondary winding of the transformer 3l is connected with the cathodes of rectiers 32 and 33, whose common anode is connected with one terminal of a smoothing capacitor 34. The intermediate tap of the secondary winding of the transformer 31 is connected with the other terminal of the smoothing capacitor 34 so that a D.C. voltage is produced therebetween. Consequently, the potential becomes positive at the intermediate tap of the secondary winding of the transformer 31 and negative at the common terminal of the rectiflers 32 and 33. A transistor 37 is also provided whose base is connected with the positive line through a Zener diode 36. The base of the transistor 37 is also connected with the collector of the same transistor through a xed resistor 35, said collector in turn being connected with the negative line, to thereby constitute a yvoltage regulator circuit so that a constant D.C. voltage appears between points A and B. This voltage energizes a lamp 49 so that a predetermined degree of illumination may be maintained irrespective of any variation taking place in the source voltage. This precaution is necessary because the variation in the quantity of light ltered by the bubbles produced in the washing drum may be undetectable by the photosensitive element from the variation in the illumination of the lamp if the latter variation is significant and this may lead to a great error in the rinsing operation. The emitter of the transistor 37 is connected with each one terminal of switch S10 or 46, electromagnetic clutch 45 and lamp 49. The other terminal of the switch S40 or 46 is connected with the positive line through a serial connection of a fixed resistor 41, CdS photo-cell 42 and switch S9 or 43. Further, the emitter of the transistor 37 is connected with the contact u of '.1 switch S8 or 39 whose common Contact is connected with the positive line through a capacitor 40. The Contact b of the switch S4 or 39 is connected between the fixed resistot- 41 and the CdS photo-cell 42, and further with one end of a potentiometer 44, the other end of which is connected with the positive side. The movable contact of the potentiometer 44 is connected with the base of a transistor 47. The potentiometer 44 serves as an adjuster for setting the degree of rinsing effect, The emitter of the transistor 47 is connected with the positive line through a xed resistor 48, while the collector of the transistor 47 is connected with the other end of the electromagnetic clutch 45. The switch S9 or 43 operates in such a timed relation with the switch S6 or 26 as will be described hereinafter.

The control circuit thus arranged effects its detecting operation only while the switch S9 or 43 is closed, and thus this switch is a timing switch for detecting the degree of rinsing effect. The switches S7 or 38 and S8 or 39 operate entirely in synchronism with each other; that is, during the period other than the rinsing cycles the switch S7 or 38 is open and the switch S8 or 39 closes its contact a. After the rinsing cycle begins, the switch S7 or 38 is closed while the switch S8 or 39 is changed over so as to close its contact b to detect the degree of rinsing effect. The switch S or 46 is operatively interlocked with the electromagnetic clutch 45.

Referring now to FIG. 7, ythere is schematically shown the interior mechanism and arrangement of the time switch. The rotation of 4the time switch drive motor 28 is transmitted through a transmission gear 50 to a main cam group 51 and a dial shaft 52. When the electromagnetic clutch 45 is energized, the transmission gear 50 is vertically displaced into a raised position as shown by dotted lines, so that the rotation of the time switch drive motor 28 is not transmitted to lthe cam group. Simultaneously therewith, the switch S10 or 46 is urged to close its contact by the raised shaft of the transmission gear 50. When the transistor 47 is rendered non-conductive, the electromagnetic clutch 45 is deenergized to return the transmission gear 50 to its original position to permit the rotation of the drive motor 28 to ybe transmitted again and to open the switch 'S10 or 46 to bring the entire arrangement to its initial state.

The switches S1, S2, S3, S4, S5, S7 and S8 or 21, 22, 23, 24, 25, 38 and 39 are actuated by the main cam group 51, while the switches S6 and S9 or 26 and 43 are actuated by a cam (not shown) provided between the time switch drive motor 28 and the transmission gear 50. The other switch S10 or 46 is actuated by the electromagnetic clutch 45 as previously described.

With the above-described arrangement, the washing operation is started by placing the clothes to be washed in the washing drum and rotating the dial shaft 52 to set it at the starting position. The time cycle representing the operative relationship of the various switches is shown in FIG. `8, in which thick solid lines denote the closing of the switch contacts.

During the water supply the switch S1 or 21 and the contacts a of the switches, S2 or 22, S5 or 25 and S4 or 24 are closed -to actuate the water supply valve 30 so as to supply water into the washing drum. At the same time a voltage is applied to the transformer, -but the control circuit does not operate yet because the switch Sr, or 38 is open.

When a predetermined water level is reached in the .washing drum, the water level switch S4 or 24 changes over to close its contact b to thereby stop the water supply and to energize the pulsator drive motor 29 which is thus driven for rotation to star-t the washing operation. Concurrently therewith, the time switch drive motor 28 also starts rotating, so that the switch S6 or 26 changes over to alternately close its contacts a and b every 30 seconds to automatically reverse the rotation of the pulsator 2. The rotation of the time switch drive motor 28 also causes the rotation of the main cam group 51 and dial shaft S2 which controls the associated switches through the transmission gear 50. After the washing time has passed in this way, the switch S2 or 22 changes over to close its contact a, thus permitting the water supply to be resumed. When a predetermined water level is reached in the washing drum, the switch S4 or 24 changes over to close its contact b so as to rotate the pulsator drive motor 29, while the switch S3 or 23 remains closed to continue the water supply, and thus the rinsing operation begins with the water overflowing lthrough the overflow port 3. As the Water supply valve 30 is in the energized state at this instant, the transformer 31 connected in parallel therewith produces a predetermined A.C. voltage in the secondary winding thereof. The A C. voltage is converted into a D.C. voltage -by the recters 32 and 33 and smoothing capacitor 34 and then adjusted to a predetermined DJC. voltage level by the Zener diode 36, xed resistor 35 and transistor 37. Also, since the switch S8 or 39 has its contact a closed now, the capacitor 40 is electrically charged at the above-mentioned predetermined voltage.

During that while the time switch drive motor 28 also continues rotation, but the circuit begins to detect the degree of rinsing effect upon the lapse of a predetermined time after the rinsing cycle starts.

The purpose of setting such a predetermined time is to provide a length of time to sufficiently stir the detergent and dirt sticking to the washed fabric and the inner wall of the washing drum to thereby permit uniformly stirred overflow to ow into the sampling box 7, and to prevent any erroneous detection.

When that predetermined time has passed, the switch S7 or 38 is closed to light the lamp at a predetermined intensity by the aforementioned constant D.C. voltage. Simultaneously, the switch S8 or 39 changes over to close its contact b whereby the charge stored in the capacitor 40 is discharged as the base current of the transistor 47, which is thus switched on to actuate the electromagnetic switch 45 so as to lbring the transmission gear 50 into the raised position as shown by dotted lines in FIG. 7. This causes the switch S10 or 46 to be closed so that the control circuit is ready to start the detection of the rising eifect, At this time, the rotation of the time switch drive motor 28 is not allowed to be transmitted to the main cam group 51 and dial shaft 52 and thereby the related switches are maintained in the position at the start of the detecting operation, whereas the time switch drive motor 28 itself still continues rotating to actuate the switch S6 or 26 to thereby reverse the rotation of the pulsator automatically.

The switch S9 or 43 operatively associated with the switch S6 or 26 closes its contact only for 3 seconds at intervals of 6.0 seconds so as to connect the CdS photocell 42 with the control circuit, whereby the monitoring of the rinsing effect is maintained.

The switches S6 or 26 and S9 or 43 are in such a relationship as shown in FIG. 8, and the relationship is shown by enlargement in FIG. 9. The pulsator drive motor 29 stops its rotation for 3 seconds to reverse the direction of rotation. Five seconds prior to this stoppage, the switch S9 or 43 closes its contact only for 3 seconds. This closing of the switch S9 or 43 takes place at intervals of one minute, and this means that the switch 'S9 or 43 is closed only while the pulsator is rotating in a particular direction. Thus, a timing relation is establishd so that the detection of rinsing effect may be carried out only while the pulsator is rotating in the particular direction.

The foregoing is an example of timing arrangement for the detection, and any other timing scheme may be employed if the switch S9 or 43 is arranged only so as not to be closed during the while the pulsator is stopped to reverse the direction of rotation and during the short period immediately after the pulsator has again started its rotation. This is because when the pulsator is rotating its centrifugal force causes the water level to be higher in the area adjacent to the overflow port than at the center,

of the washing drum, whereas the water level becomes uniform upon stoppage of the pulsator so that the water level in the area adjacent to the overflow port declines to permit no overflow. This in turn causes the bubbles to disappear in the sampling box 7 and thereby the quantity of light received by CdS 42 is increased to cause erroneous detection. Also, the movement of the water begins in some delay after the start of the pulsator started its rotation, and a `certain length of time is required before overflow takes place. Therefore, the control circuit must be prevented from operation when there is no overflow. To prevent such so-called malfunction, the switch S9 or 43 is provided and set to a certain relationship with the switch S6 or 26 which controls the pulsator drive motor 28. According to the present embodiment, this relationship is as shown in FIG. 9.

This relationship is not necessarily critical when use is made of the illustrated type of sampling box, whereas it is important in order to prevent any possible malfunction when use is made of other types of sampling boxes, for example, the one of such a type that is mouated at a suitable location between the bottom of the washing drum and the overow port in such a manner as to permit rinsing water to be forced into the sampling box by the water supply stream and in which the detection is made not of the transparency of the overflown rinsing water but of the transparency or light transmissivity of part of the rinsing water in the washing drum.

The pulsator may generally take an impeller-like shape which produces different types of water streams for clockwise rotation and counter-clockwise rotation, and accordingly the manner in which the bubbles are formed in the body of rinsing water in the washing drum is also different depending on the rotational direction of the pulsator. This difference in the bubble formation affects the light transmissivity of the rinsing water. For example, the resistance of CdS is smaller for the clockwise rotation of the pulsator, while it is greater for the counter-clockwise rotation of the pulsator. Thus, the resistance of the CdS varies with each reversal of the pulsators rotation, and the respective values gradually decrease as water supply and rinsing operation proceed.

Ideally, the detection of rinsing effect should be accomplished by detecting only the degree of rinsing. However, since erroneous detection may be caused by the difference in water stream between the clockwise and the counter-clockwise rotation, the switch S9 or 43 is set to operate at time intervals of one minute for the purpose of energizing the control circuit only in the Iperiod during which the pulsator is rotating clockwise, for example.

Thus, the detection of the rinsing effect is done at interi vals of one minute. If, however, the switch S9 or 43 is open, the transistor 47 is rendered conductive by its base voltage determined by the fixed resistor 4l and the position of the movable contact of the potentiometer 44. When the switch S9 or 43 closes its contact, the CdS 42 will be connected in parallel with the potentiometer 44. The resistance value of the CdS 42 is so high as to ensure the base voltage required to maintain the transistor 47 is conductive, but as the rinsing operation proceeds to increase the dilution ratio, the quantity of light received by the CdS is also increased as described with respect to FIG. 3, with a result that the resistance value of the CdS 42 is reduced until it reaches the set value. Thereupon, if the switch S9 or 43 is closed, the terminal voltage of the CdS drops, and accordingly the base voltage, is reduced until the transistor 47 is switched off. Thus, the electromagnetic clutch is deenergized.

The degree of rinsing effect may be adjusted as desired by means of the potentiometer 44.

The capacitor 40 is connected in parallel with the CdS 42 for the following reason. If the detergent in the washing drum should be insufficiently stirred and thereby cause a part of the water in the washing drum to be lower in the concentration of the detergent, no bubbles would be produced even when such water overflows and falls into the sampling box 7. If the switch S9 or 43 happens to close at this moment, the absence of bubbles in the sampling box would cause the circuit to operate. However, such a phenomenon is usually momentary, and the erroneous operation due to such a phenomenon can be prevented by keeping the detector inoperative by the delaying effect of the capacitor 40. It will thus be seen that the capacitor 40 is directed to the purpose of preventing any malfunction as well as of forcing the transistor 47 into conductive state at the starting point of the operation of the control circuit to thereby actuate the electromagnetic clutch 45. When the rinsing cycle thus proceeds to render the transistor 47 non-conductive, the electromagnetic clutch 45 is electrically disconnected to return the transmission gear 50 to its original position shown by solid lines in FIG. 7, whereby the rotation of the time switch drive motor Z8 is again transmitted through the gear 50 to the main cam group 5l and dial shaft 52 while the switch S10 or 46 is opened so as to never to allow the base current of the transistor 47 to flow. In other words, once the control circuit has completed the detection of the rinsing effect, the electromagnetic clutch will never operate. The purpose of this will be apparent from the following description. Assume that the switch S10 or 46 is always closed. Sometimes, it may happen, even if the rising cycle is completed to leave little or no detergent in the water, that there are created some fine bubbles in the sampling box due to air mixed in the water. These fine bubbles will be sensitively detected by the CdS photo-cell 42, so that the CdS will increase its resistance to turn on the transistor 47 and thus actuate the electromagnetic clutch. Thereby the main cam group 51 and dial shaft 52 will step. However, the main cam group 51 and dial shaft 52 will soon resume their rotation, because such fine bubbles will disappear relatively quickly and the switch S9 or 43 is closed thereby to turn off the transistor 47.

If the above-described phenomenon repeats itself, the main cam group 51 will rotate intermittently and thereby the rinsing time will be longer than necessary. To prevent such an undesirable result, the switch S10 or 46 is provided in operative association with the electromagnetic clutch.

When the completion of the rinsing cycle is detected in the described manner, the main cam group `Sll and dial shaft 52 resume their rotation, and upon lapse of a predetermined time, the switch S7 or 38 opens to cut off the power to the control circuit and the switch S8 or 39 returns to the contact a position, thereby resetting the circuit to its initial position. Thereafer, the positional relationship between the switches becomes the same as that during the first draining operation so as to drain the water from the washing machine. Upon lapse of a predetermined time thereafter, the switch S1 or 21 opens to cut off the power to the entire electrical circuit and complete the entire washing cycles.

According to the present invention as has hitherto been disclosed, the rinsing cycle takes place after the cycles of water supply, washing, drainage and water supply, and upon the lapse of a predetermined time after the rinsing cycle begins, the degree of rinsing effect is examined. If the rinsing effect is found to be still insufficient, the main cam group 51 of the time switch is stopped from rotating, and it is re-started when a sufficient rinsing effect would be attained. Thus, drainage is started upon lapse of a time which is sufficient to provide a complete and satisfactory rinsing effect.

In the above-described embodiment of the present invention, description has been made with respect to the electrical circuit arrangement using transistors, though the present invention is not limited thereto. Use may be made of what are called variable impedance elements. For example, a thyristor may be used, being driven by the charge stored in the capacitor.

FIG. l0 shows another example of the sampling box. With this arrangement, some of the overflow from the overow port ows through a branch pipe C into a drain hose 4 while the other part D of the overflow passes through the sampling box 7 into the drain hose 4. In the sampling box 7 there are produced bubbles by the falling water as previously described. Beneath the bubbles the overilow water maintains a certain water level F. In the embodiment shown and previously described, all the overow flows through the sampling box 7 and therefore, if the rate of water supply is increased, the overflow is also increased to raise the water level F. This would cause the bubbles to be forced upward by the water level F and to ow out of the air hole 12 until no bubbles are left in the sampling box, which is thus lled with overflow alone. This will in turn cause the CdS photocell to receive a greater amount of light which may actuate the electrical circuit. In the present embodiment, however, the branch pipe C provided at the entrance to the sampling box 7 serves to maintain the inflow of water at a constant rate and accordingly the water level F is also maintained at a suitable height, whereby stable operations are ensured even if the rate of water supply varies. The principle of this is thus: when the water supply is greater, the overow flowing through the overflow port is also greater so that the overflow ows into the drain hose 4 at a considerably higher velocity due to the difference in level. This imparts a greater suction which will cause a greater amount of air flow E to be forced into the falling water as shown by the dotted line, and this air flow E prevents some of the .overflow from flowing into the sampling box 7. If the overflow is smaller in quantity, the suction caused thereby is also smaller so that the interruption by the air is reduced to allow the entry of more overflow into the sampling box. Thus, although there would be a tendency that the greater is the rate of the overow, the greater quantity of water would tend to flows into the sampling box 7, this tendency is suppressed by the air ow E. Conversely, the smaller is the rate of the overflow, the more readily can the water enter the sampling box 7 and a constant rate of inow is maintained at all times. Therefore, even if the rate of water supply is varied, the water level in the sampling box 7 is maintained constant so that bubbles are not forced out of the sampling box as long as the overflow contains detergent therein, and this ensures reliable operation of the washing machine.

What we claim is:

1. A washing machine comprising a washing drum, a pulsator mounted within said washing drum, a time switch providing a series of cycles from washing through rinsing to drainage, and rinsing detection means for stopping the drive of said time switch during the rinsing cycle until the rinsing cycle is completed, said rinsing detection means having a luminous element and a photosensitive element for detecting the transparency of washing water, and control means for controlling the drive system of said time switch and the photosensitive element circuit, whereby completion of the rinsing cycle is automatically detected by the variation in the output of said photosensitive element, wherein said time switch comprises a motor, a transmission gear actuated byv an electromagnetic clutch, and a main cam group for controlling various switches, said main cam g-roup receiving the rotation of said motor transmitted through said transmission gear to thereby control said various switches, whereby said electromagnetic clutch energized in accordance with the operation of said electrical rinsing detection circuit engages and disengages said transmission gear with its associated gear train so as to control the transmission of the rotation of said motor to said main cam group to thereby complete the rinsing detection.

2. A washing machine comprising a washing drum, a pulsator mounted within said washing drum, a time switch providing a series of cycles from washing through rinsing to drainage, and rinsing detection means for stopping the drive of said time switch during the rinsing cycle until the rinsing cycle is completed, said rinsing detection means having a luminous element and a photosensitive element for detecting the transparency of washing water, and control means for controlling the drive system of said time switch and the photosensitive element circuit, whereby completion of the rinsing cycle is automatically detected by the variation in the output of said photosensitive element, wherein said pulsator automatically reevrses its rotation, and said rinsing detection circuit is operable in synchronism with a switch for automatically reversing the rotation of said pulsator.

3. A washing machine according to claim 2, wherein said pulsator automatically reverses its rotation, and said rinsing detection circuit is operable only when said pulsator is rotatingin one of its rotational directions.

4. A washing machine comprising a washing drum, a pulsator mounted Within said washing drum, a time switch providing a series of cycles from washing through rinsing to drainage, and rinsing detection means for stopping the drive of said time switch during the rinsing cycle until the rinsing cycle is completed, said rinsing detection means having a luminous element and a photosensitive element for detecting the transparency of washing water, and control means for controlling the dri-ve system of said time switch and the photosensitive element circuit, whereby completion of the rinsing cycle is automatically detected by the variation in the output of said photosensitive element, wherein said rinsing detection means includes a sampling box disposed at a location of the washing drum so as to permit washing water to be flowed into and out of said sampling box by a stream of water supply, and said luminous element and photosensitive element are disposed in opposed relationship with said sampling box interposed therebetween, and further wherein means is provided to stir the rinsing water in said sampling box with a stirring impeller to forcibly expedite bubbling of the water so as to increase the quantity of light shielded by the bubbles formed.

S. A washing machine comprising a washing drum, a pulsator mounted within said washing drum, a time switch providing a series of cycles from washing through rinsing to drainage, and rinsing detection means for stopping the drive of said time switch during the rinsing cycle until the rinsing cycle is completed, said rinsing detection means having a luminous element and a photosensitive element for detecting the transparency of washing water, and control means for controlling the drive system of said time switch and the photosensitive element circuit, whereby completion of the rinsing cycle is automatically detected by the variation in the output of said photosensitive element, wherein said rinsing detection means includes a sampling box disposed at a location of the washing drum so as to permit washing water to be owed into and out of said sampling box by a stream of water supply, and said luminous element and photosensitive element are disposed in opposed relationship with said sampling box interposed therebetween, and further wherein a branch pipe and an air hole are provided in the vicinity of the entrance to said sampling box connected with said overow port of the washing drum so that the rate of overflow and rate of air ow introduced may be maintained in proportional relationship with each other, whereby the rate of rinsing water flowing into said sampling box is made constant.

References Cited UNITED STATES PATENTS 2,430,668 ll/l947 Chamberlin 68-12 R 3,114,253 12/1963 Morey et al `68--12 R 3,279,481 10/1966 Sones et al 68-l2 R X WILLIAM I. PRICE, Primary Examiner 

